On Sun, Sep 27, 2009 at 5:36 AM, Steven D'Aprano
<st...@remove-this-cybersource.com.au> wrote:
> I'm pretty sure the answer to this is No, but I thought I'd ask just in
> case...
>
> Is there a fast way to see that a dict has been modified? I don't care
> what the modifications are, I just want to know if it has been changed,
> where "changed" means a key has been added, or deleted, or a value has
> been set. (Modifications to mutable values aren't important.) In other
> words, any of these methods count as modifying the dict:
>
> __setitem__
> __delitem__
> clear
> pop
> popitem
> setdefault
> update
>
> Of course I can subclass dict to do this, but if there's an existing way,
> that would be better.
>
>
> --
> Steven
Depending on what you're doing you could use something like this:
(Note that it doesn't work on empty dicts, and you'd have to "reset
it" if your dict ever became empty after processing.)
def f(d):
while True:
i = iter(d).next
try:
while True:
try:
i()
except RuntimeError:
yield True
break
else:
yield False
except StopIteration:
if not d:
break # else we'd enter an infinite loop.
In [1]: d = {23: 18}
In [2]: check = f(d).next
In [3]: check()
Out[3]: False
In [4]: d['cats'] = 'lol'
In [5]: check()
Out[5]: True
In [6]: check()
Out[6]: False
In [7]: d.clear()
In [8]: check()
Out[8]: True
In [9]: check()
---------------------------------------------------------------------------
StopIteration Traceback (most recent call last)
/home/sforman/<ipython console> in <module>()
StopIteration:
HTH,
~Simon
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